PROCEEDINGS: GEOLOGICAL SOCIETY 453 



process even for trained men and accurate skilfully written descriptions 

 are a great aid. 



Adolph KnopE: Present tendencies in geology: metalliferotts deposits. 



The chief problems and tendencies at the present time in the study 

 of ore deposits are: (i) the reaction against undue dependence on the 

 microscope, whether it be the petrographic or the metallographic 

 microscope; (2) the determination of the influence of pressure and tem- 

 perature in producing the mineral facies of ore deposits, and as a corol- 

 lary, the zonal distribution of ore deposits around intrusive centers; 

 (3) the application of physical chemistry to the problems of ore deposi- 

 tion; (4) the reaction against the extreme acceptance of the doctrine 

 of the origin of ore deposits from magmatic waters; (5) the application 

 of physiography to economic geology, especially with reference to the 

 origin of gold, iron, manganese, and nickel deposits as related to the 

 development of peneplains; (6) the bringing of economic geology into 

 closer touch with economics and with the larger social policies of the 

 State; (7) the taking of inventories of the world's chief mineral resources; 

 and (8) the estimation of mineral reserves by improved methods, espe- 

 cially by applying the modern methods of statistical analysis. The war 

 and the problems arising from the war as to the international adjust- 

 ment of mineral supplies have particularly emphasized the need for 

 detailed information on the world's mineral resources, especially for 

 information of a quantitative character. 



Ralph W. Stone, Secretary. 



